This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn.

Routine upper gastrointestinal (GI), radiographic series as part of the workup for bariatric surgery. Patient preoperative management.

Treatment; Diagnosis.

Cost-effectiveness analysis.

Morbidly obese patients about to undergo gastric bypass operations.

Hospital. The study was carried out in North Carolina, USA.

The effectiveness and resource use data were collected between 1980 and 1994. The price date was not clearly reported.

The estimates for clinically significant preoperative findings by radiography and influence on subsequent patient management were derived from a single study.

The costing was undertaken retrospectively on the same patient sample as that used in the effectiveness study.

From a total of 814 patients who underwent gastric bypass surgery during the study period (1980-1994), 657 patients successfully completed upper GI series performed in the 'standard manner'. Of these 657 preoperative x-rays, 393 (59.8%) were reported as normal studies, whereas the remaining 264 (40.2%) reported abnormalities.

Case series from a single centre. The duration of follow-up is not relevant to the study.

The principle used in the analysis is not relevant. The primary health outcome measure was clinically significant preoperative findings by radiography and influence on subsequent patient management.

Of the 264 radiographic examinations showing abnormalities, six (0.9%) were clinically significant. Two of these were gallstones large enough to be palpable at surgery, and would have been found and removed even without the examinations. The other four were asymptomatic renal stones in patients without hematuria.

The results of this study demonstrate that routine GI series are not justified in the preoperative evaluation of the morbidly obese.

Since the effectiveness analysis found no difference in clinical benefit between the workup for bariatric surgery with a routine upper gastrointestinal series and that without, the economic evaluation was based on the differences in costs only.

The costing consisted of charges per radiographic examination (without the methodology used in arriving at and components of this 'unit charge' figure being reported). The price year was not provided. The quantities of resource use were reported separately from the costs. The quantity/cost boundary adopted was the hospital.

US dollars ($).

No sensitivity analysis was performed.

Not applicable.

By sparing a patient the radiologic examination,$741 in charges would be saved, which amounts to an annual figure of $111,150 at an annual rate of 150 procedures performed.

Not applicable.

The GI series can be omitted as a routine preoperative test in the evaluation of a gastric bypass. Retrospective review of individual tests and their effects on therapy offers a reasonable and, more importantly, a defensible approach to determining whether they should be maintained or dropped as part of the workup.

The reason for the choice of comparator ('no routine upper gastrointestinal series performed as part of the preoperative workup for bariatric surgery') was clear. As the surgery in the morbidly obese represents a major expense, the study attempted to address the question of whether X-ray examination could safely be omitted as a cost-saving measure. You, as a user of this database, should consider whether these are widely used health technologies in your own setting.

The validity of the study results may be questionable due to the retrospective, uncontrolled study design, and aspects related to ethics and feasibility which may have been important considerations in the choice of such a design.

Whilst only the direct costs associated with the procedure in question were included in the analysis, the methodology employed in deriving the unit costs (charges) was not described. The price date was not provided.

The authors' conclusions may not be justified given the uncertainties in the data. The issue of generalisability was not addressed.

Further studies are needed in order to verify the results found by this study. To this end, randomized controlled trials with sizes based on prior power calculations, would be desirable.

Partly funded by the Faculty Practice Plan and by institutional support of the Department of Surgery of East Carolina University School of Medicine.